Is there a role for post-treatment PET/CT following chemoRT for Stage III NSCLC?

The data from RTOG 0235 are certainly intriguing, but I don't think we have sufficient information to employ this in routine clinical practice.

In fact, I think there are quite a few challenges, including, but not limited to:

1. What is the true sensitivity for post-CRT PET/CT for LR failure? This was a highly select group of patients on a propsective trial. When you start including a wide range of treatment regimens, histologies, patients, etc., how predictive is it?

2. What options does a patient...

RTOG 0235/ACRIN 6668 demonstrated that in stage III patients treated with chemoradiation, elevated post-treatment SUV of regional lymph nodes, both the absolute value (SUVmax > 5.2) and the percentage of residual activity (>25.84%) compared to the pretreatment SUV were associated with inferior local-regional control. Local failure rates were 2.7x higher in patients with a PET response above the absolute threshold, with a long-term probability of locoregional control at only ~25-30%. It is import...

For those of us not connected to RTOG trials, and familiar with 0235 and 1106 questions, eligibility, and status, simply stated, PET is expensive, and it needs to be medically necessary to get it. The first question in a patient treated with chemotherapy and radiotherapy for NSCLC, what will you do with the information? If the studies concern "boost" or "biologically adaptive therapy" to areas that are PET +, an issue still is when is the best time to get the scan: immediately?, 1 month, 3 month...